The Numbers Game: What Your Charleston Crawl Space's Moisture Levels Are Telling You

Jonathon Hart • March 15, 2025

Crawl Logic Lowcountry

Why We Base Everything On These Numbers

AND SHOOT VIDEOS IN THE INSPECTION TO SHOW YOU WHAT WE FIND

Every crawl space tells a story through its numbers.


And here in Charleston, with our famous humidity and coastal climate, those numbers can tell quite a tale.


The thing is, most homeowners don't know how to read these signs until it's too late - when they're already dealing with musty odors, warped floors, or worse.


I know talking about moisture levels and humidity percentages might sound boring, or maybe even pretentious.


But stick with me here.


Understanding these numbers isn't about showing off - it's about protecting your home.


And honestly?


It's simpler than you might think.

(843) 214-2962

Welcome to Crawl Logic Lowcountry!


Breaking Down the Key Numbers

Let's start with the big one: 80% relative humidity.


That's your first warning sign. When people ask me what relative humidity means, I tell them straight up - it's just how much moisture is hanging out in the air at any given temperature. Think of it like your crawl space's fever thermometer.


When that number crosses 80%, your crawl space is sending up a red flag. At this point, your home's wooden structure starts acting like a sponge, soaking up all that extra moisture from the air.


And in Charleston? With our subtropical climate? This happens more often than you'd think.


Here's what makes this percentage so crucial: it's the tipping point. Once you cross that 80% line, the moisture content in your wood starts climbing. And just like dominoes, when that first one falls, the others aren't far behind.




The Danger Zone Numbers

Now, here's where things get serious.


Once your wood moisture content hits 16%, you're in what I call the danger zone.


Even with this "lower" number, mold can start creeping in - especially in dark spaces with poor air movement.


And let's be honest, that describes most crawl spaces in Charleston.


At 19%, we hit what inspectors call "active mold growth."


Personally, I think that's a funny term - like mold is ever really inactive?


But this is the number that shows up on those official CL-100 reports.


By this point, you're not just risking mold - you're guaranteed to have it.


Then there's 23%. This is where things can get expensive.


At this level, depending on how thick your wood is, you might start seeing actual movement.


Those squeaky floors?


That slight bounce when you walk across the living room?


That's not just annoying - it's a sign your home's structure is being compromised.

The Solution in Action

So how do we fix this? It's actually pretty straightforward.


We create what's basically a giant sealed airspace under your home.


Think of it like a controlled environment - like a climate-controlled storage unit, but for your crawl space.


In this sealed space, we install a commercial-grade dehumidifier - and yes, we intentionally overpower it.


Why?


Because in Charleston's climate, you need that extra muscle.


But here's the key: we also install sensors to monitor everything.


Because even the best dehumidifier in the world won't help if it stops working and nobody notices.


The goal is simple: lower the moisture content in your wood and keep it there.


When we get it right, your crawl space reaches what we call homeostasis - a fancy way of saying everything stays stable exactly where it should be.

Crawl Logic Lowcountry

Protecting Your Charleston Home

This is why we take the time to explain all this to every homeowner we work with. We document everything with videos during inspection, and we're happy to walk you through every step.


Because these numbers aren't just statistics - they're the early warning system for your home's health.


Want to know what your crawl space's numbers are saying?


We'll give you a straight answer - even if that means telling you everything's fine right now.


Our inspection process includes detailed moisture readings, complete video documentation, and a clear explanation of what we find.

(843) 214-2962
Man with mustache, questioning, text:
By Jonathan Hart August 20, 2025
Look, I know you're probably expecting another crawl space story, but sometimes you find something so good you've got to share it. Today, I'm talking about pho - specifically, the incredible pho broth I just discovered at H&L Supermarket in North Charleston.
A man in a car says
By Jonathan Hart August 20, 2025
Just got a text from someone we'd quoted for crawl space work. They were worried about possible structural issues, and it got me thinking about how many Charleston homeowners get pushed into expensive foundation repairs they might not even need.
By Jonathan Hart August 9, 2025
Here's a story that drives me crazy because it was completely preventable. We got called to check out a crawl space that had been encapsulated by another company. Now, the original work wasn't terrible - not the best I've seen, but it was doing its job. At least until one small part failed: the condensate pump.